Much has been written in recent years about the short- and long-term consequences of concussions sustained in sports, combat, and accidents. However, there appear to be no steadfast rules guiding the definition of concussion. Researchers investigated the signs, symptoms, and clinical histories used by athletic trainers to define concussion in individual college athletes engaged in contact sports. The investigators found a heterogeneous collection of acute clinical characteristics -- a "concussion spectrum," which they discuss.

Share This

What does it mean to have a head concussion? Much has been written in recent years about the short- and long-term consequences of concussions sustained in sports, combat, and accidents. However, there appear to be no steadfast rules guiding the definition of concussion: the characteristics associated with this type of traumatic head injury have shifted over time and across medical disciplines. Within the context of a larger longitudinal investigation of the biomechanical factors in play that correlate with concussions in collegiate helmeted contact sports, researchers in New England and Virginia used data they obtained to investigate which signs, symptoms, and clinical histories were used by athletic trainers to define concussion in individual players. The investigators found that a heterogeneous collection of acute clinical characteristics currently exists for those events diagnosed as concussion in college athletes engaged in contact sports.

Related Articles

Together with her colleagues, Dr. Duhaime, Director of Pediatric Neurosurgery and of Neurotrauma and Intensive Care in the Neurosurgical Service of Massachusetts General Hospital, examined concussions diagnosed in athletes participating in helmeted contact sports (football and ice hockey) at three universities: Dartmouth, Brown, and Virginia Tech. Both male and female athletes participated in the study. The students' helmets were outfitted with Head Impact Telemetry (HIT) System™ technology to record and measure peak linear and angular acceleration of impacts. The helmets were worn during practice sessions and games throughout two to four seasons. The investigators did not attempt to influence how trainers and team medical personnel defined concussion operationally, but instead relied on the clinical characteristics deemed indicative of concussion by the universities' athletic departments.

More than 486,000 head impacts were recorded in 450 athletes, and concussion was diagnosed in 44 of these athletes (48 concussions) by team medical staff. Unlike concussions more often diagnosed in emergency departments, where a single, identified contact event leads to a loss of consciousness or other clear alteration in consciousness, most diagnoses in this sports setting were based on self-reports by athletes, and only a few were based on changes in athletes' clinical conditions that were observed by others. Thirty-one concussions could be directly associated with a specific impact, whereas a relationship with a specific impact could not be verified in the other cases of concussion. Only half of the athletes noted symptoms immediately after a contact event; in many athletes, the onset of symptoms was delayed. The most common reported symptoms were mental clouding, headache, and dizziness; only one case involved a loss of consciousness. The diagnosis of concussion by trainers often occurred in an even more delayed fashion: the diagnosis was made immediately after the event in 6 cases and at a later time in the other cases (median 17 hours postinjury).

In general, the mean peak linear and angular accelerations for specific impact events that could be directly linked to concussions tended be in the high percentiles for the sports examined; however, there was considerable variability in the ranges of these measurements (mean peak linear acceleration 86.1 ± 42.6 g [range 16.5.9 g], mean peak angular acceleration 3620 ± 2,166 rads/sec2 [range 183,589 rads/sec2]).

The variety of signs and symptoms, the imprecise timing of symptom appearance and relationship to a specific contact event, the lack of externally observed findings, and the broad ranges of the linear and angular accelerations of the impacts that coalesce in a diagnosis of concussion in college sports make it difficult to identify predictors of acute, intermediate, and long-term risks of adverse consequences resulting from sports-related head impacts. By describing the heterogeneity inherent in diagnoses of concussion as a "concussion spectrum," the authors point out the need for renewed efforts to determine which factors -- clinical, mechanical, genetic, or others -- influence outcomes in patients with single as well as repeated head impacts. The authors point out that while a clinical diagnosis is important to protect players from additional and potentially more serious consequences, it is also possible that athletes who do not receive the diagnosis of "concussion" may be at similar risk. Likewise, it is possible that some players who receive a diagnosis of concussion do not fall into a high-risk category for specific consequences.

The authors note that there is still much to be learned, and that the terminology in use can sometimes oversimplify a more complex set of processes that still need to be teased apart. In their response to an accompanying editorial, they state, "By carefully characterizing exactly what we are talking about and by continued investigation, which will take more time ... , neurosurgeons and others will be best positioned to offer effective treatments and to advocate knowledgeably for appropriate injury-prevention strategies."

Featured Research

Mar. 31, 2015  Researchers have illuminated an important distinction between mice and humans: how human livers heal. The difference centers on a protein called PPAR alpha which activates liver ... full story

Mar. 31, 2015  Researchers have recorded the first direct observations of the micro-scale mechanisms behind the ability of skin to resist tearing. The results could be applied to the improvement of artificial skin, ... full story

Mar. 31, 2015  Fewer than half of the physicians trained in the United States in 2013 received formal education or training on the subject of exercise, according to new research. "There are immense medical benefits ... full story

Mar. 31, 2015  Memory and as well as connections between brain cells were restored in mice with a model of Alzheimer's given an experimental cancer drug, researchers report. "With this treatment, cells under ... full story

Mar. 31, 2015  Increasing state alcohol taxes could prevent thousands of deaths a year from car crashes, say researchers, who found alcohol-related motor vehicle crashes decreased after taxes on beer, wine and ... full story

Mar. 31, 2015  Alcoholism takes a toll on every aspect of a person's life, including skin problems. Now, a new research report helps explain why this happens and what might be done to address it. "The clinical ... full story

Mar. 31, 2015  A new population of 'memory' immune cells has been discovered by scientists, throwing light on what the body does when it sees a microbe for the second time. This insight, and others like it, will ... full story

Mar. 31, 2015  Coronary heart disease and stroke, two of the leading causes of death in the United States, are diseases associated with heightened platelet reactivity. A new study in humans suggests an underlying ... full story

Mar. 31, 2015  A new study had researchers seeking answers to why the therapeutic benefit afforded by SSRIs was so limited in children and teenagers. If researchers can uncover the biological mechanisms preventing ... full story

Featured Videos

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015)  The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports.
Video provided by Reuters

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015)  Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline.
Video provided by Washington Post

S. Leone in New Anti-Ebola Lockdown

AFP (Mar. 28, 2015)  Sierra Leone imposed a three-day nationwide lockdown Friday for the second time in six months in a bid to prevent a resurgence of the deadly Ebola virus. Duration: 01:17
Video provided by AFP

Related Stories

July 9, 2014  The American Academy of Neurology (AAN), the largest professional association of neurologists and a leading authority on sports concussion, is releasing a new position paper that states doctors have ... full story

Jan. 9, 2014  A brain protein, S100B, which may soon be detected by a simple finger-stick blood test, accurately distinguishes a sports-related concussion from sports exertion, according to a ... full story

Oct. 14, 2013  Recent scientific findings have raised the fear that young athletes may fare worse after sustaining a sports-related concussion than older athletes. Researchers compared symptoms associated with ... full story

May 2, 2012  Junior Seau’s apparent suicide might shock the sports world, but not concussion specialists. NFL players have a higher rate of depression, substance abuse, and dementia. This is thought to be ... full story

Nov. 1, 2010  The American Academy of Neurology is calling for any athlete who is suspected of having a concussion to be removed from play until the athlete is evaluated by a physician with training in the ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.